Hydraulic valve control for reversing transmission



1.. D. CARUFLEL' 2,781,056

RAULIC VALVE CONTROL FOR REVERSING Feb. 12, 1957 United States Patent GF HYDRAULIC VALVE CONTROL FOR REVERSING TRANSMISSION ApplicationFebruary 12, 1953, Serial No. 336,607 2 Claims. c1. 137-624) Thisinvention relates to a reversing transmission assembly and moreparticularly to a hydraulic valve control for successively actuating aplurality of hydraulic instrumentalities in the operation of saidtransmission.

Transmissions of the type embodying the valve herein illustrated aregenerally employed for service with a power driven machine such as atransit cement mixer, various types of earth moving machinery or otherindustrial machines in which a relatively heavy load of material is tobe moved. Such machines or equipment are moved forward or reverse, andwhen such transmission is applied to a cement mixer or other earthmoving machinery and the like, carrying heavy loads, the transmissionmust be capable of quickly stopping and reversing the load withoutplacing an undue load on other parts of the machine. In the case of acement mixer carrying a heavy load of wet cement, weighing in theneighborhood of from four to seven or eight tons, the machine isconstructed so that it can be slowly agitated in transit and furtherconstructed so that the cement drum can be reversed in order todischarge the contents thereof, and again quickly reversed if need be,to cut off the discharge of wet cement.

The torque required to rotate the drum of a cement mixer or othermachine is many times the torque produced by the engine, and thetransmissions as are presently employed to transmit and multiply theengine torque to said drum and to drive same at a speed of approximatelyabout ten revolutions per minute are in general quite bulky and massivebecause they employ a reversing mechanism operating on the output sideof the reduction drive transmission.

With such mechanisms, the control is usually manually operated and thetiming of such successive operations is of vital importance. Speed inchanging from forward to reverse drive is required, but the movementfrom forward speed to a full stop and then to reverse or vice versa mustbe had very quickly, but not so instantaneous as to subject the variousoperating parts of the machine to excessive strains and stress which maysnap or break such machine mechanisms.

An object of the present invention is to provide controlling meanssatisfactory for a transit cement mixer and other power machines orequipment by constructing a manually operated control valve soconstructed to suc cessively exhaust certain hydraulic lines beforesupplying fluid under pressure to other lines. V

For a more detailed understanding of the invention, reference may be hadto the accompanying drawings illustrating a preferred embodiment of theinvention showing one application thereof, wherein like characters referto like parts throughout the several views, and in which:

Fig. l is a sectional view through the valve.

Figs. 2 to 6 inclusive are enlarged fragmentary diagrammatic detail plansectional view of the valve showing various positions assumed by saidvalve parts.

One type of machine, for which the present power transmission means isparticularly practical is a transit cement 2,781,056 Patented Feb. 12,1957 mixer, and such an application is preferably illustrated anddescribed herein, but obviously a mechanism of this character may beusefully applied to machines and powered equipment other than transitcement mixers.

A control valve assembly C is illustrated in Fig. l as having an inlet60. A special valve 62 is rotatably mounted in the valve casing 63 andis actuated to distribute the oil under pressure to oil passages 64, 65and 66 which respectively connect with passages 67, 68 and 69. Passage67 preferably leads to the brake means of a reversing transmission whilepassage 68 and passage 69 preferably lead to the transmission clutches.

In most instances the valve 62 is mounted within a sleeve 61 in thevalve assembly to reduce wear to a minimum and to generally provide animproved valve assembly having ideal operating characteristics. In Figs.2 to 6 inclusive, there are shown diagrammatic illustrations of thevalve structure, and for purposes of clearness, the sleeve detail isleft out, since the sleeve per se is not a part of this invention.

When at rest, the disposition of the valve takes the position indicatedin Figs. 2 and 6, the oil under pressure being fed to the brake, becausepassage 67 is aligned with valve passage 64. The valve is rotated fromthe position of Fig. 2 counterclockwise to bring passage 68 intoregistration with the valve outlet passage 65 actuating one clutch ofthe transmission. To actuate another clutch, the valve is rotatedclockwise from the Fig.- 3 position to Fig. 4 position and said valvepassage 64 passes the passage 67, before valve passage 66 is moved intoregistration with passage 69, thus momentarily setting the brake andbringing the transmission to a complete stop prior to being reversed.

A suitable bleed isprovided from the brake to the interior of thetransmission casing and as soon as the valve 62 cuts ofi the supply ofoil under pressure to this passage, the pressure in passage 67immediately drops, permitting the rapid retraction of the brake.

Referring to Fig. 5, it will be observed that the valve isbeing' rotatedclockwise and the passages 68 and 65 are just about to be moved out ofregistration and the annular passage or recess 77 is about to be movedinto registration with passage 68, thus venting the passage 68 as saidannular passage is in registration with passage preferably 78 leading tothe interior of the transmission casing. It is noted also that thedimensions from the passages 65 and 66 to the respective ends of thegroove 77 are slightly less than the arcuate dimensions of ports 68 and69, providing a momentary overlap between pressurizing and venting.

Likewise, as the valve is moved counterclockwise from the position ofFig. 4 where passages 69 and 66 are in registration, to the positionillustrated by Fig. 3, the passage 69 is brought into registration withthe annular passage 77 after passages 69 and 66 are removed out ofregistration, so as to vent the pressure in passage 69. In moving thevalve from the position (Fig. 3) to position (Fig. 4) or vice versa, thepassage 64 is always momentarily brought into registration withpassage67 leading to the brake.

The spring pressed pawl or pin 80 rides in the annular slot 81 havingannularly spaced recesses 82 so disposed as to locate the valve inreverse, forward or neutral position. This slot 81 also limits themovement of the valve.

In the application of the present invention to a transit cement mixer,the speed of the unit (a cement drum in those requiringfrequents-reversal onthedrives bledi the part'io"be dfive'n away may notbe of a speed as low as the cement drum of a transit" mixer, but'in allby meehanism; operableio. function at engine; speed: i As such.speedsare -redueed'irom engine speed or. direct drive to 451,-. 1021,- 50:1,.orslOOLto- 200: 1, .the; torquelis CO1? respondinglyincreasedTherefore,-. a reversing -transmis sion 'operable on machineelementssoperating atesuch ree dueed speeds-must be.correspondinglymassive; and: oft such construction.asto,carry;thesewheavy loads;'

. In the presentassemblyathe -reversing:mechanism is e operable onedrivinggand driven; shaitsoperatingat engine; speed-Land:thisscombinationyisqspeeially,nsefuh and-adva-m tageous with powendriven maehines sueh asr transit con cretemixersandheavrearthimovingmachines, especially Thus-aquicle acting positive. valvemeehar1ismsuchas; hereinillustrated and described-isespecially;applieableetoeat vreversing transmission -.op erableat engine speed.

It will bev apparent .to; thoseiskilled in r theartto? which thisinvention pertains-that variousx-changes-and modificw tions may be madetherein, without .-departing, from the spirit oftheinvention-1.onfrOmihescope ofatherappended claims.- 7

l. A uni'tary.hydrauliewalve' control means applicable for controlling'a plurality} of: coactingg'operatingr means.

' strnctureyhavinganarcuate-exhaustpassageseparateirommission-havingdriving anddrivenelements andaplurality. ofpressure actuated means, said:runitaryg-hydraulicvalver control meanscom'pirisingga {valve-1t casing; and a- "valve: 7

structurerr otatably oscillatingntherein, said .:valve': casing: havinga fluid pressure inlet means, a vent; outlet means-,

and n a plurality; of pressure: outlet means respectively;

adapted for successive connectiomv1ith=said pluralityeofi pressure:actuated; means ofiisaid-'=mechanism, one- 0f said pressure: outlet:rneans: being;angular-1y;-offset "frornione side of said-ventoutletlmeansyanother oi said pressure '7outletgmeans-beingiangularlyofisetanrequal;distancefrom;

the opposite sidfi-fcff saidkwent toutletimeansg said valu'er' structureprovided with: a f receiver communicating. at all times withthe.fiuidipressureiinletz of said-.casingand' having separate; outletpassages cornmunicating with said: receiver and adapted toibe successifvelyrplaeede-into com-- .xnunicatien with said: plurality; ob -pressure routletmeans ofv said-*valve'casing, said-value .structurehaving; anareuate- I removed-therefromandprior to the succeedinggopening; V

exhaustpassage:separaterfrom;said;outlet passages andarranged: for open:conneietiongat all times with said; vent.

arcuate exhaust passage, another of said outlet passages beingangularlyi offsetzarn equal distancefrom theother end'eofsaidrarcuateiexhaustmassage, .th'e arcuateEd-imen arcnatezexhaustcpassa'gejibeingssubstantially equal Jtoibutslightlyless-tharrrthe arcuate, dimensions ofi said: offset" pressure routletmeanswhereby toprov-ide a'slight overlap.

. between pressurizing andexhaustingofgsame said arcuate exhausttpassagetherebygbeing disposed-.in-timed relationshipwith respect .to said:offset: outlet passages on oscillation of said valve structure toexhaust a previously pres? surizedz-ofis'ettoutlet meanssubstantiallyimmediatelyjbesions from-saidofis'etzoutletpassa'gesitorthe ends' r'offsaid- V passage, thei arcuatedimensions from: said offset outlet fore pressurization is removedtherefrom and prior to the succeeding opening of the other offset outletmeans, said arcuate exhaust passage of said valve structure comprisingan arcuate annular groove extending about the periphery of said valvestructure and communicating at all times with said vent 'outletmeans ofsaid casing, said arcuate groove moved to vent only such offset outletmeans which areout of registration with 7 pressurized outlet passages,

2. A unitary hydraulievalve.control meansiapplicable; for controllingaplurality ofx'Ipressure 'aetuatedi-means, said unitary hydraulicvalvecontrol;meansecomprising. a 'valve. casing, and a valve. structurerotatably oscillating therein; said valve" casing having" a fluidpressure inlet means, a vent outlet-meansgflandaaiplurality of pressureoutlet means'respectively adapted for successive connec.

7 tion with said plurality of pressure actuated means of said mechanism,ones of. saidrpressuree outlet means being angularly ofiset from one.side of asaid -ventioutlet means;

another or saidupressurer outlet. meansab'eing. angularly;

ofiset an equaledistance, from the opposite side. of. saidventcoutlet-means,\-;saidrvalvestructure provided. with a receivercommunicating. at allf'timeswith'the fluid -p res'-- sure; inletoftsaidg'casing and having separate. outlet pas.-sagescommunicatinggwithsaid receiver-and. adapted tojbe. successively.placed into' communication .with .saidplurality i oifpressureioutlet.means-ofsaid valvecasing, said valve.-

said outlet passages -one of saidoutlet passages being angurlarl-yeoifsetr frornuone end of said arcuate: exhaust/passage,another/coi said. outlet passages. being; angularly offset an equal.distancefromsthe'othen end=of-said arcuateeexhaust p assages tothe-sends otsaidsarcuate exhaustpassa'gebeing substantially-:equalto butslightly less thantthe arcuate: di-, mensionsof said=-ofiset pressureoutlet means whereby to provide as slight overlap 9 between.pressurizing and; ex haustingsof SQXTIQy-Slid. arcuatezexhaust,passagethereby beingg disposediinrtimed relationship Lwithrespect to-said oifset outlet passages on oscillation of saidQvalvestruc-f ture-to exhaust-a previously pressurized offset outlet; means.substantially. immediately before pressurization is" of the; otheroffsetoutlet means,-;said' casingihavingga third pressurefoutlet means,and -aitl1irdoutlet passageg in said valve.-. structure disposedsubstantially:medially between said-'ofiset outlet Ipassages-and,.lopposite.to .said." arcuate-exhaust passage, whereby-said third.outlet v vpas-s sage will be momentarily connected withsaidthird outletmeans subsequent to exhausting of: the. one .oh setioutle t meanstands-prior; tor openinguof the other offset outlet.

means- ReferencesLCi'ted in the file of. this patent. v

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